Currently, Hardware-In-the-Loop (HIL) testing is the defacto standard for ECU verification and validation at the majority of the Commercial Vehicle OEMs and Tier1 suppliers. HIL Testing is used to shorten development and testing time for both engine and machine control systems. In order to use this process, many of these companies have to develop and maintain expertise in the area of Model-based development (MBD). This paper introduces an approach which allows for the effective use of HIL systems without having to directly work in a MBD environment.Many HIL tests can be done with stimulus and response analysis of the ECUs, given core knowledge of the expected behavior of its control software and I/O subsystems. For hardware interface and diagnostics validation, this open-loop testing of the controller may suffice. It is important to provide the tester with capabilities to easily modify these stimuli and evaluate the responses. The nature of many control and implement systems in the Commercial Vehicle segment mandates this as the primary approach for testing. There are also many types of dynamic plant models and tools that are available as commercial-off-the-shelf (COTS) systems. The integration of these models into a modular testing system allows for a seamless approach to validating closed-loop control systems. The easiest approach to using these models is to provide for a simple mapping of these models to a fully capable test system.This paper discusses the needs and challenges for this new approach to HIL testing, taking into account the wide range of applications for different areas of development for Commercial OEM engine and mechanical control ECUs. An overview of a commercially available toolset to accomplish these tasks is shown. Finally an analysis of the advantages of this approach, given the potential needs for growth into more complex testing will be discussed.